In recent years, to power consumers, the introduction of distributed power supplies such as renewable energy like solar-electric power generation, self-power generation, and storage batteries has been advanced, and energy management systems for cooperatively controlling them have been developed. A technology for interchanging power in such a manner as to supply surplus power and to procure insufficient power according to varying power supply and power consumption by not only the single energy management system that controls the distributed power supplies under the management thereof but also by the energy management systems that cooperate/collaborate with each other will be further needed.
Patent Document 1 proposes a power system in which a plurality of power consumers judge the presence or absence of a power shortage or a power surplus therein, one consumer at occurrence of the power shortage receiving power from the other consumer, one consumer at occurrence of the power surplus supplying power to the other consumer.
Patent Document 2 proposes a power demand management system that causes a power consumer in which surplus power will occur to perform a power interchange by specifying a power apparatus of a power consumer located close to its own power consumer and by notifying the consumer of an estimated time period of the occurrence of the surplus power and an amount of power less than or equal to the amount of surplus power.